Note: Descriptions are shown in the official language in which they were submitted.
CA 02510989 2005-06-28
Hybrid Window WalUCurtain Wall System and Method of Installation
FIELD OF INVENTION
[0001] The present invention relates generally to exterior building envelope
finishing
systems, and more particularly to improvements over curtain wall and window
wall
systems and the like.
BACKGROUND OF THE INVENTION
[0002] The current approach to the construction of large highrise commercial
or
residential buildings is to first construct a self supporting structure of a
roof, floors
and interior bearing members (including posts, beams, bearing walls, columns,
and
other structural supports), generally out of concrete and/or steel, and then
to encase
this structure with an exterior shell. The exterior shell provides an
insulating,
weather-proof, generally air-tight and aesthetic cladding, but essentially no
structural
strength. The two most common types of exterior shell systems for such
buildings are
called "window wall" systems and "curtain wall" systems.
[0003] In window wall systems, rigid panels of a manageable size and weight
are
prefabricated to roughly the same height as the spacing between adjacent pairs
of
concrete floor slabs. These rigid panels are inserted between the concrete
floor slabs
and are sealed with caulking. These rigid panels can take on a variety of
exterior
appearances but in general they consist largely of clear glass panels (i.e.
windows,
which are referred to as "vision glass" in the industry) along with opaque
glass or
metal infill panels (these opaque glass panels are generally referred to as
"spandrel
glass"). These rigid panels are framed with horizontal and vertical runs of
metal
mullions, headers, sills and trim as required. Most window wall systems are
constructed of aluminum, although some may be of steel.
[0004] A vertical cross-section of a typical window wall system is presented
in Figure
1. In the interest of simplicity, the rigid panels 10 are shown to consist of
vision glass
only, but combinations of vision glass, spandrel glass, and other finishing
materials
are also often used. As shown, the rigid panels 10 are framed with top
channels 12
and bottom channels 14, and vertical mullions (not shown). The framed, rigid
panels
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are then placed between adjacent pairs of concrete floor slabs 16, 16'. In
such an
installation, caulking 18, 18' is required at both the top and bottom of the
rigid panels
10. In this figure, the faces of the concrete slabs are finished with a metal
panel 20,
which will typically be painted.
[0005] Window wall systems suffer from a number of problems the most
significant
of which is poor long-term performance. As noted above, regular window wall
are
sealed with caulking between the rigid panels and the floor slabs - eventually
this
caulking is going to break down and leakage will occur. The concrete floor
slabs keep
moving, mainly through winter and summer expansion and contraction cycles.
This
cycling keeps compressing and decompressing the rigid frames repeatedly,
placing a
strain on the caulking until it begins to break down. The length of time that
it takes
for this breakdown to occur depends on the environment and the specifics of
the
installation, but these components often start opening up after two to five
years, thus
requiring maintenance. Once the caulking joints start opening up, water will
get into
the system and damage both the window wall system and the building interior.
This
deterioration and long-term performance is a severe problem with window wall
systems.
[0006] Of course, the caulking must also be installed properly in the first
place, which
is not an easy task. Even pinholes or small cracks may allow water to leak
into the
building, particularly on the windward side of the building which experiences
significant levels of air pressure across the cladding system. If too thin a
layer of
caulking is applied, or if the surfaces are dirty, oily or wet when the
caulking is
applied, the seal may fail very quickly or be ineffective right from the
beginning.
[0007] Conventional curtain wall systems are similar to window wall systems in
that
they consist of prefabricated rigid panels which form a non-structural
exterior
cladding for the building. Like window wall systems, these rigid panels
consist
largely of vision glass with suitable infill panels and framework. They are
sized to be
of manageable size and weight, but are taller than window wall panels because
they
equal to the building's storey height, rather than the distance between the
slabs.
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[0008] A vertical cross-section of a typical curtain wall system is presented
in Figure
2. 1n this case, each pre-fabricated rigid panel 30 has been shown to consist
of both
vision glass 32 and spandrel glass 34, but any combination of vision glass,
spandrel
glass, sheet metal panels and other finishing materials may also be used. The
rigid
panels 30 are framed with a bottom channel 36 and vertical mullions (not
shown).
Each bottom channel engages with the sprandrel glass 34 of the rigid panel 30
mounted below it.
[0009] The big difference between curtain wall systems and window wall systems
is
that the rigid panels 30 of the curtain wall system are hung on the building
structure,
usually from floor to floor, each module being supported by connectors on the
outer
area of each concrete floor slab 16, 16'. Rigid curtain wall panels are
stacked on each
other in parallel rows and adjacent modules are typically connected together.
[0010] That is, rather than the rigid panels fitting between the concrete
slabs 16, 16'
as in the case of window wall systems, they hang from the slabs like curtains,
sitting
proud of the slab with each panel being sealed to the next with gaskets. In
this
arrangement, the rigid panels 30 of the curtain wall system are sealed to one
another
which minimizes the effect of thermal cycling. Hence, this makes a shell which
is
essentially continuous, and entirely outside the structure of the building.
[0011 ] Conventional curtain wall systems generally do not have the
caulking/leakage
problem of window wall systems, but they have problems of their own.
[0012] To begin with, conventional curtain wall systems have a gap between the
vision glass 32 / spandrel glass 34 layer and the faces of the concrete slabs
16, 16'
which introduces problems with regard to sound transmission, and smoke and
fire
safing between individual floors. While these issues can be addressed with
suitable
sealing systems, the larger the gaps are, the more expensive and time
consuming they
are to fill and they result in a possible failure point for the system.
[0013] A related problem is that conventional curtain wall systems have
vertical
mullions which run continuously from the bottom to the top of the building.
These
vertical mullions are hollow and boxed-shaped in cross-section, so they
essentially act
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like a duct for the flow of sound and smoke between floors. The interiors of
these
vertical mullions are not sealed between floors and it would be very expensive
and
inconvenient to do so.
[0014] Also, conventional curtain wall systems require anchors 38 which are
embedded directly in the concrete floor slabs to support their rigid panels
30. The
supply, layout and installation of these embedded anchors 38 is a costly item,
particularly in high labor cost markets. Curtain wall systems are mounted to
the top
of, or on the face of the concrete floor slabs 16, 16' with one embedded
anchor 38
taking care of each vertical mullion. Because each embedded anchor 38 is
supporting
a great deal of load, including both vertical loads and in/out loads, these
embedded
anchors are 38 typically cast into the concrete floor slabs 16, 16'. Expansion
anchors
and other types of concrete fasteners simply are not strong enough to support
such
loads reliably.
[0015] Attempts have been made to address the problems of conventional window
wall and curtain wall systems. For example, window wall systems have been
provided with an upper channel which runs along the underside of the upper
floor
slab, the rigid panels 10 being fitted into this channel. This allows for some
vertical
movement, but the interface of the rigid panel and the horizontal channel
still has to
be caulked, so it will eventually break down; and this additional interface
introduces
another point for possible air and water leakage. None of these modified
window wall
or curtain wall systems have been very successful.
[0016] Recently, high-end residential condominium developers, building
envelope
consultants and architects in Canada and the USA have been asking for a low
cost
curtain wall system for use in their projects to replace commonly used window
wall
systems. The uniform response from developers and architects was that they are
tired
of the poor long-term performance of window wall systems and of the standard
"prison look" effect due to restrictions in module width and wide mullion
assemblies.
Also, the appearance of slab-edge metal cover panels 20 was not aesthetically
pleasing.
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[0017] Because window wall systems are installed between the concrete floor
slabs,
there is necessarily a horizontal panel 20 at least at every floor slab. As
well, because
window walls are being designed with very small and weak vertical mullions in
the
interest of cost reduction, they must be supplied with a larger number of
vertical
mullions, resulting in more vertical lines. Rather than using four- or five-
foot
spacings for vertical mullion modules, it is now common to see vertical
mullions
spaced on three-foot to four-foot centres. The large number of vertical
mullions
creates a prison-like look with these vertical lines every three feet or so.
[0018] Any new window wall or curtain wall system must also take installation
cost
into consideration. Installers are expensive, especially in markets where the
cost of
living is high, such as in Manhatten, New York. Because of the high labour
costs and
low productivity levels in such environments, it is also desirable to employ
as much
factory pre-fabrication as possible. This improves quality, increases
productivity of
site labourers and reduces damage and loss of materials due to weather
conditions,
dirt, and storage and handling activities on the construction site.
[0019] There is therefore a need for an improved window wall or curtain wall
system,
provided with consideration for the problems outlined above.
SUMMARY OF THE INVENTION
[0020] It is therefore an object of the invention to provide an improved
window or
curtain wall system and method of installation for such a system, which
obviates or
mitigates at least one of the disadvantages described above.
[0021 ] One aspect of the invention is broadly defined as a unitized exterior
building
envelope system for a building comprising: individual framed panels, supported
with
vertical mullions on their sides, the vertical mullions interconnecting
adjacent ones of
the individual framed panels; each of the vertical mullions being notched to
accommodate the thickness of a concrete floor slab; each of the individual
framed
panels being attached to the top of a lower floor slab and the underside of an
upper
floor slab using anchors fastened respectively to the top and underside
surface of the
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concrete floor slabs; and one of the anchors being fixed to the vertical
mullion, and
the other of the anchors slidably engaging with the vertical mullion
[0022] Another aspect of the invention is broadly defined as a method of
installing a
wall system comprising the steps of shipping unitized modules to the site
fully
assembled with vision glass and spandrel glass or other infill materials
already shop
installed; the integral sleeve anchors being preinstalled into the vertical
mullions; the
unitized modules being set in place temporarily between two floor slabs; the
bottom
sleeve anchors sliding inside the vertical mullions being moved /adjusted to
correct
elevation and being fixed by two fasteners through the side wall of the
vertical
mullion; the unitized modules then being set plum, and the top sliding anchors
being
pushed up to the underside of the floor slab and fixed by means of expansion
anchors
or other fasteners suited to the slab construction.
[0023] The invention provides a building envelope system that has the
performance of
a curtain wall system, but uses rigid panels that are installed between
floors. This
results in a high performance installation at a lower labour cost, with easier
installation of sound and fire sealing.
[0024] This summary of the invention does not necessarily describe all
features of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] These and other features of the invention will become more apparent
from the
following description in which reference is made to the appended drawings
wherein:
[0026] Figure 1 presents a vertical cross-sectional view of a window wall
system as
known in the art;
[0027] Figure 2 presents a vertical cross-sectional view of a curtain wall
system as
known in the art;
[0028] Figure 3 presents a vertical cross-section of a cladding system in a
broad
embodiment of the invention;
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r
[0029] Figure 4 presents a vertical sectional view of a cladding system in a
preferred
embodiment of the invention, where the expansion joint is located at the top
of the
slab;
[0030] Figure 5 presents an enlarged detailed sectional view of the cladding
system of
Figure 4;
[0031] Figure 6 presents a enlarged detailed orthogonal view of the cladding
system
of Figure 4;
[0032] Figure 7 presents a vertical sectional view of a cladding system in a
preferred
embodiment of the invention, where the expansion joint is located at the top
of the
slab;
[0033] Figure 8 presents a enlarged detailed sectional view of the cladding
system of
Figure 7;
[0034] Figure 9 presents a enlarged detailed orthogonal view of the cladding
system
of Figure 7; and
[0035] Figure 10 presents a flow chart of a method of installation for a
cladding
system in an embodiment of the invention.
DESCRIPTION OF THE INVENTION
[0036] The invention adapts and modifies a conventional unitized curtain wall
system
so that it can be installed between concrete floor slabs similar to a
conventional
window wall system. Modifications were made without negative impact to the
superior performance, appearance options and installation capabilities of a
conventional unitized curtain wall system.
[0037] The main problems of the known systems were solved by notching a
conventional unitized curtain wall systems (Sota Glazing's Millennium Series
and
Thermo 3 Series were used in the development of the invention) around the
concrete
floor slabs without interrupting the continuous integral gasketed, airseal
system of the
curtain wall system. A conventional window wall system is completely
interrupted
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between concrete floor slabs and relies on caulked joints between window
frames and
the concrete floor slabs to create a continuous airseal barner.
[0038] The notching of the curtain wall system around the concrete floor slabs
also
solves the fire safmg and sound attenuation problems usually associated with
the use
of conventional curtain wall systems. It interrupts the flow through the
vertical
mullions, and it also brings the rigid panels much closer to the face of the
concrete
floor slabs, so it is much easier to create a seal between floors.
[0039] However, simply notching the structural vertical members of a
conventional
unitized curtain wall causes a structural system problem. This problem is
solved by
using a sliding sleeve anchor to support either the top, or the bottom of a
given rigid
panel. This sliding sleeve anchor will be described in more detail with
respect to
Figure 3 hereinafter.
[0040] The notching of the system around the floor slabs now allows the
architect
new design flexibility to incorporate glass, granite, terra cotta or aluminum
metal
panels in front of the floor slabs. When using a conventional window wall
system, the
floor slabs are always covered with a formed metal panel, slab edge cover. The
invention is capable of supporting and incorporating all the same commonly
used
infill materials as a conventional curtain wall system, including for example:
monolithic and insulated glass units, granite, limestone, stainless steel,
aluminum
plate and composite panels, metal panel shadow boxes, insulated galvanized and
aluminum back pans.
[0041 ] A broad embodiment of the invention is presented in the vertical cross
section
diagram of figure 3. Specifically, this figure shows that individual framed
panels 40
are supported with vertical mullions 42 on their sides. The vertical mullions
42
interconnect horizontally adjacent individual framed panels 40, which is
common
teaching in the art. Particular to the invention though, is that each of the
vertical
mullions 42 is notched to accommodate the thickness of the concrete floor
slabs. As
well, the individual framed panels are attached to the top of a lower floor
slab and to
the underside of an upper floor slab by means of two anchors 44 which are
fastened
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respectively to the top and underside surface of the lower and upper concrete
floor
slabs. As noted above, it is desirable that one of these two anchors 44 be
fixed to its
vertical mullion 42, while the other be able to slide within it. This allows
the system
to move, and accommodate expansion and contraction of the concrete floor
slabs,
seismic motion, etc.
[0042] The system of the invention does not need the costly embedded anchor
plates
used in conventional curtain wall systems because it is anchored to the top
and bottom
of the floor slabs by means of expansion anchors through the integral mullion
sleeve
anchors. The sound attenuation and fire safing performance of the invention
are
superior to that of a conventional curtain wall system due to the fact that
the vertical
mullions are interrupted at each floor slab, thereby preventing a "smoke stack
effect"
(transfer of sounds and fumes to the next floor) within the interior cavity of
the
vertical mullions.
[0043] The invention provides a system which at least matches the performance
and
appearance of a unitized curtain wall with the important distinction that it
installs
between floors like a regular window wall system. This is the only similarity
between
the system of the invention and any of the window wall systems currently
available in
the market. The system of the invention is notched around the floor slabs and
allows
the use of glass floor spandrels in lieu of the slab edge, metal panel covers.
Because it
is a true unitized curtain wall system, it employs the horizontal expansion
assemblies
with gaskets, making the typical sealant joints between floor slabs and window
wall
frames obsolete. The system of the invention also employs fully integrated,
fixed and
sliding anchors enabling ease of installation while allowing for construction
slab
tolerances and vertical live load movements between floor levels.
[0044] Thus, the invention solves the detrimental issues of the design
features of a
conventional curtain wall system without diminishing the performance and
design
flexibility of a conventional unitized curtain wall system. The preferred
embodiments
of the invention also provide other advantages, as described hereinafter.
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DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE
INVENTION
[0045] The invention can be applied in many different manners, some
embodiments
exploiting only a selection of the advantages of the invention rather than all
of them.
In some cases, for example, it may be decided to compromise on certain
advantages to
reduce costs.
[0046] There are two main variations of the invention, both of which employ
one
sliding anchor and one fixed anchor per vertical mullion. Figures 4, S and 6
present a
variation where the sliding anchor is mounted on the underside of the upper
floor slab,
and the fixed anchor is mounted on the top surface of the lower floor slab.
Figures 7,
8 and 9 present the opposite arrangement - where the sliding anchor is mounted
on the
lower slab, and the fixed anchor is mounted on the upper. The arrangement of
Figures
4, 5 and 6 is preferred because it is easier to fire proof.
[0047] Figure 4 presents a vertical cross section of the arrangement where the
sliding
anchor is mounted on the underside of the upper concrete floor slab. In this
particular
arrangement, the rigid panels 40 may be pre-fabricated with a large section of
vision
glass 50 and a smaller section of spandrel glass 52. The vision glass SO of
course,
could also be replaced with an insulated panel, a laminated panel or a
monolithic
panel of some sort. It could also be finished with any typical architectural
material
such as granite, limestone, stainless steel, aluminum plate or composite
panels.
Similarly, the spandrel glass panel 52 could also be filled with an insulated
panel, a
laminated panel, or a monolithic panel consisting of any architectural
material
including granite, limestone, stainless steel, aluminum plate or composite
material.
[0048] It is preferable that the vision glass 50 employ high quality panes of
glass.
Some systems use inexpensive glass units with a single seal. If the single
seal fails,
the units are going to break down and start fogging up. A single-sealed glass
pane is
lower in cost than a double-sealed unit, but provides an inferior product,
hence it is
preferable to use double-sealed units. With the invention there is no
limitation on
what kind of vision glass 50 could be installed. Regular vision glass is one
inch thick,
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comprising '/4 inch glass, a %z inch air space, and '/4 inch glass. However,
the
invention can also be implemented with triple glass units, which are often 2
inches or
2 '/2 inches thick, or other glass systems.
[0049] The vision glass 50 and spandrel glass 52 portions are vertically
interconnected with one another via an extruded aluminum transom 54, which is
finished with an exterior aluminum or stainless steel cap 56 and pressure
plate. Both
the transom 54 and cap 56 may be the same as those used in regular curtain
wall
systems, and are known in the art. Both are available in many standard and
custom
shapes. An alternate option is to have a capless horizontal joint with
structural
silicone applied to the glass.
[0050] Between the concrete slab 16 and the spandrel glass 52 a layer of
insulation 58
is generally required, such as mineral board insulation with an aluminum foil
backing
or metal back pan (as required for the installation). This insulation runs the
full
horizontal length of each rigid panel 40, and is typically bonded to the
aluminum
frame members during the pre-fabrication of the rigid panels 40, with
reinforced
aluminum tape or in some similar manner.
[0051 ] Additional mineral board insulation 60 and a smoke seal 62 are
installed in the
field as required to comply with local fire codes. Typically, this work is
done by a
specialized contractor and not by the installer of the curtain wall or wind
wall system.
[0052] The top edge of each pre-fabricated rigid panel 40 is finished with an
extruded
aluminum header 64, which includes a horizontal airseal gasket 66. In
combination
with a horizontal sill extrusion 68 on an adjacent rigid panel 40 mounted
above, which
finishes the bottom of each pre-fabricated rigid panel 40, the extruded
aluminum
header 64 and horizontal airseal gasket 66 make up a horizontal expansion
assembly
which absorbs vertical interstory movement. With this arrangement, the thermal
cycling of expansion and contraction can be accommodated without requiring a
large
bead of caulking as in window wall systems. An enlarged detail of the
arrangement of
components 52, 54, 56, 58, 64 and 66 is presented in Figure 5.
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[0053] Note that in the system of the invention all of the joints are
gasketed; no
caulking or other sealants are used for weatherproofing. Gasketed seals slide
against
each other, and will last far longer than other sealing systems without
breaking down.
The gaskets are preferably made of high-grade materials such as silicone. Less
expensive EPDM (Ethylene Propylene Diene Monomer) or santoprene thermoplastic
gaskets will not last as long, though some markets may demand them because of
their
lower cost.
[0054] It is also notable that the sills, headers and mullions of the
invention are
designed to protect the gaskets from having to face environmental conditions
directly.
In Figure 5, for example, it is clear that the horizontal airseal gasket 66 is
protected
by a labyrinth of aluminum extrusions.
[0055] The rigid panels also include, of course, vertical mullions 68. The
vertical
mullions 68 in Figures 4, 5 and 6 are all notched at the top, to accommodate
the "top
of slab" installation for the sliding anchor 74. The vertical mullions in
Figures 7, 8
and 9 are all notched at the bottom to accommodate the "bottom of slab"
installation
for the sliding anchor. The notch must be wide enough to accommodate the
sliding
anchor, but still thick enough to allow room for insulation to be installed
between the
spandrel glass 52 and the face of the concrete slab 16, 16'.
[0056] In the preferred embodiment of the invention, these vertical mullions
68 are
two-piece aluminum mullions with separate female and male portions that snap
together. The invention provides a unitized system, so each independent
unitized
rigid panel 40 will have a male portion of a vertical split mullion on one
side and a
female portion on the other. These complementary pairings of vertical mullions
simply connect together as the building wall is assembled in a sideways
direction.
[0057] Typically, these vertical mullions 68 snap together without fastening
and can
slide with respect to one another. One could use mechanical fasteners such as
sheet
metal screws to hold them rigidly together, but this would generally not be
desirable.
The slipping connection between the halves of a given vertical mullion 68
allows for
thermal movement and building seismic movement.
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[0058] Rather than using vertical split mullions, some installations use
"stick" curtain
wall systems. These "stick" systems are essentially systems of vertical and
horizontal
tubes which are assembled in the field, rather than being pre-fabricated like
the system
of the invention. Though the invention could be applied to a stick system,
there are
many disadvantages to such systems, particularly the high installation cost.
Pre-
fabrication and pre-assembly are desirable for at least two reasons. As noted
above,
field labour costs are very high in some urban areas - much higher than they
are in
more industrial areas. As well, pre-fabrication results in a much higher
quality
product because more of the work is done under controlled factory conditions.
Attempting to do the same work in the field results in losses due to weather
conditions, dirt, people damaging and losing materials, etc.
[0059] In the perspective sectional drawing of Figure 6, three other details
of the
vertical mullions 68 are also clear. Firstly, each vertical mullion 68 is
finished with an
exterior aluminum or stainless steel cap and pressure plate 70. As noted
above, such
caps are available in many standard and custom shapes and colours. Secondly,
each
vertical mullion 68 incorporates a vertical air seal gasket 72 which is
integrated into
the split mullions. This vertical air seal gasket 72 also mates and/or
overlaps with the
horizontal air seal gasket 66 to create a continuous gasketed air seal system.
Thirdly,
the extent of the notching in the vertical mullion 68 is shown with the dotted
line 84.
As noted above, there is a sufficient gap between the vertical mullion 68 and
the
concrete floor slabs 16, 16' to allow a layer of insulation to be installed.
[0060] All of the vertical and horizontal sills, headers, mullions and other
similar
framing components are shown in the figures in a simplified form in the
interest of
clarifying the points of invention. It would be known, however, to one skilled
in the
art to employ the necessary holes and edges for effective drainage, thermal
breaks, etc.
[0061 ] Each vertical mullion 68 is fastened to the concrete floor slabs 16,
16' with
two concrete anchors 74, 76; one at the top and one at the bottom. In the
arrangement
of Figures 4, 5 and 6, the concrete anchor 74 at the top, can slide within the
vertical
mullion 68, while the concrete anchor 76 at the bottom, is fastened to the
vertical
mullion 68 with two fasteners 86 (self tapping sheet metal screws or the
like). These
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two fasteners 86 transfer the dead load and provide a moment connection
between the
vertical mullion 68 and the concrete anchor 76.
[0062] In the preferred embodiment, the concrete anchors 74, 76 consist of
simple
extruded aluminum channel uprights which are welded to bases made of aluminum
plate. The precise dimensions required will depend on the parameters for a
given
application but are easily calculated. Depending on the vertical mullion
design where
the concrete anchors 74, 76 are engaged into a frame it may be tapered or not
at the
end condition. Two of such variants on the concrete anchors 74, 76 are shown
in the
figures. Figure 6 shows a variant of the concrete anchors 74, 76 having a
right-angled
square at the top, while Figure 5 shows anchors with a slope or taper. The
advantage
of a tapered end condition is that it allows the installer at the site or
during the
assembly to guide the anchor into the vertical mullion more easily between the
engagement points of the vertical mullion.
[0063] As noted above, aluminum is typically used for all of the system
components
(mullions, anchors, etc.), and is generally accepted in the art over steel.
Aluminum is
lighter to handle and fabricate, and does not rust like steel. As well, if one
was to
manufacture both steel and aluminum systems, one would have to separate all
the
processes because the same equipment cannot be used to fabricate the two
materials.
[0064] These concrete anchors 74, 76 are fastened to the horizontal surfaces
of the
concrete floor slabs 16, 16' using standard expansion anchors 78 (or any other
suitable
type of fastener) as shown in Figure 6. This is in contrast to curtain wall
systems
which require expensive anchors, embedded into the concrete floor slabs 16,
16',
generally on the face of the floor slabs. Expansion anchors and other similar
fastener
systems cannot be used with convention curtain wall systems because they
cannot
handle the stresses which the system creates. However, comparatively
inexpensive
expansion anchors can be used with the preferred embodiment of the invention,
even
in the tallest buildings. With the system of the invention, the expansion
anchors only
have to take care of lateral loads; there is no rotational action as in the
case of curtain
wall systems, just "in and out" loads.
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[0065] The interior of the system is typically finished with two additional
pieces of
trim. The interior extruded aluminum closure trim 80 is field installed to
cover up the
mullion anchors at the underside of concrete slab 16, 16' and also provides a
mounting surface for tenant applied curtain rail or other sunshade systems. A
horizontal snap-on trim cover 82 is also typically provided at the sill
extrusion to
conceal the fasteners 78. This horizontal snap-on trim cover 82 is installed
after the
completion of the fixed anchor work.
[0066] The remaining details of the system flow logically from the description
provided herein, and would be clear to one skilled in the art. For example, at
the
corners one could install either split mullions or monolithic vertical
mullions.
Standard 45°, 90°, doglegs and other corners can easily be pre-
fabricated. The need
for these will depend completely on the building design and shape of or the
size of the
rigid panels, and it generally changes on every building. The details of these
components follow logically from the rest of the design. The difference from
existing
mullions is that the corners will be notched at the floor slab in the same way
as the
other vertical mullions.
[0067] As noted above, Figures 7, 8 and 9 present a very similar arrangement
to that
of Figures 4, 5 and 6 except that the vertical mullions are notched at the
bottom rather
than the top, and the sliding anchors are mounted on the upper side of the
lower
concrete slab rather than the underside of the upper concrete slab. Also as
noted, the
arrangement of Figures 4, 5 and 6 is preferred because it is easier to install
the
necessary fire proofing materials.
[0068] Figure 7 presents a vertical cross section of the arrangement where the
sliding
anchor is mounted on top of the lower concrete floor slab. In the same way as
the
system of Figure 4, the rigid panels 40 are pre-fabricated with a large
section of vision
glass 50 and a smaller section of spandrel glass 52. The vision glass 50 could
be
replaced with an insulated panel, a laminated panel or a monolithic panel,
and/or
finished with any typical architectural material such as granite, limestone,
stainless
steel, aluminum plate or composite panels. Similarly, the spandrel glass panel
52
could also be filled with an insulated panel, a laminated panel, or a
monolithic panel
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CA 02510989 2005-06-28
consisting of any architectural material including granite, limestone,
stainless steel,
aluminum plate or composite material. If vision glass 50 is to be used, it is
preferrable
to employ high quality double-sealed panes of glass. With the invention there
is no
limitation on what kind of vision glass 50 could be installed; 1 inch, 2 inch
or 2 '/2
inch thick systems are all fine.
[0069] Just as in Figure 4, the vision glass 50 and spandrel glass 52 portions
are
vertically interconnected via an extruded aluminum transom 54, which is
finished
with an exterior aluminum or stainless steel cap 56 and pressure plate. The
only
difference in Figure 7 is that the spandrel glass 52 portion is at the lower
end of a
given rigid panel 40, rather than at the top end. Both the transom 54 and cap
56 may
be the same as those used in regular curtain wall systems, and are known in
the art.
Both are available in many standard and custom shapes. An alternate option is
to
have a capless horizontal joint with structural silicone applied to the glass.
[0070] Because the spandrel glass 52 is at the lower end of a given rigid
panel 40, the
layer of insulation 58 will also be at the lower end. In the same way as in
Figure 4,
this layer of insulation 58 will generally be a mineral board insulation with
an
aluminum foil backing or metal back pan (as required for the installation),
and runs
the full horizontal length of each rigid panel 40, typically being bonded to
the
aluminum frame members during pre-fabrication of the rigid panels 40, with
reinforced aluminum foil tape. Additional mineral board insulation 60 and a
smoke
seal 62 are installed in the field as required to comply with local fire
codes.
[0071 ] Note that the arrangement of the extruded aluminum header 64,
horizontal
airseal gasket 66 and horizontal sill extrusion 68 are also different in this
embodiment.
While the horizontal airseal gasket 66 is basically unchanged, the top edge of
each
pre-fabricated rigid panel 40 is finished with a wider extruded aluminum
header 90 to
accommodate the width at the top of these panels, as shown in Figure 7. The
bottom
of each panel is finished with a narrow horizontal sill extrusion 92 because
this
portion of the rigid panel 40 includes the notch around the concrete floor
slab 16, 16'.
Together, the header 90, horizontal airseal gasket 66 and horizontal sill
extrusion 92
make up the horizontal expansion assembly which absorbs vertical interstory
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CA 02510989 2005-06-28
movement. With this arrangement, the thermal cycling of expansion and
contraction
can be accommodated without requiring a large bead of caulking as in window
wall
systems. An enlarged detail of the arrangement of components 52, 54, 56, 58
and 66,
90 and 92 is presented in Figure 8.
[0072] In the same way as the system of Figures 4, 5 and 6 it is also
preferred that this
embodiment be implemented with high quality silicone (or similar) gaskets, and
that
the extrusions are designed to protect the gaskets.
[0073] The rigid panels of Figures 7, 8 and 9 also include vertical mullions
94, except
that they are notched at the bottom, rather than at the top, to accommodate
the
"bottom of slab" installation for the sliding anchor 74. The notch must be
wide
enough to accommodate the sliding anchor, but still thick enough to allow room
for
insulation to be installed between the spandrel glass 52 and the face of the
concrete
slab 16, 16'. In the same way as described above, it is preferred that these
vertical
mullions 94 are two-piece aluminum mullions with complementary pairings of
male
and female mullions-halves installed on adjacent rigid panels 40, so that they
simply
connect together as the building wall is assembled in a sideways direction.
Again, it is
desirable that these vertical mullions 94 be allowed to slide with respect to
one
another to allow for thermal movement and building seismic movement.
[0074] The system of Figures 7, 8 and 9 can also be employed with "stick"
curtain
wall systems, and the same pre-fabrication methodology can be used as with the
system of Figures 4, 5 and 6.
[0075] Figure 9 presents an orthogonal sectional detail similar to that of
Figure 6.
Though there are not shown in this view, the vertical mullions 94 will be
finished with
an exterior aluminum or stainless steel cap and pressure plate. As well, each
vertical
mullion 94 incorporates a vertical air seal gasket which is integrated into
the split
mullions, generating a continuous gasketed air seal system in cooperation with
the
horizontal air seal gasket 66. The extent of the notching in the vertical
mullion 94 is
shown with the dotted line 100. As noted above, there is a sufficient gap
between the
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CA 02510989 2005-06-28
vertical mullion 94 and the concrete floor slabs 16, 16' to allow a layer of
insulation to
be installed.
[0076] As in Figures 4, 5 and 6, each vertical mullion 94 is fastened to the
concrete
floor slabs 16, 16' with two concrete anchors 74, 76; one at the top and one
at the
bottom. The concrete anchor 74 at the top, can slide within the vertical
mullion 94,
while the concrete anchor 76 at the bottom, is fastened to the vertical
mullion 94 with
two fasteners 86 (self tapping sheet metal screws or the like). These two
fasteners 86
transfer the dead load and provide a moment connection between the vertical
mullion
68 and the concrete anchor 76.
[0077] Just as in Figure 6, the concrete anchors 74, 76 are fastened to the
horizontal
surfaces of the concrete floor slabs 16, 16' using standard expansion anchors
78 (or
any other suitable type of fastener) as shown in Figure 9. This is in contrast
to curtain
wall systems which require expensive anchors, embedded into the concrete floor
slabs
16, 16', generally on the face of the floor slabs.
[0078] Also, the interior of the system is typically finished with the
interior extruded
aluminum closure trim 80 to cover up the mullion anchors at the underside of
concrete
slab 16, 16', and the horizontal snap-on trim cover 82 is also typically
provided at the
sill extrusion to conceal the fasteners ?8.
[0079] Just as with the system of Figures 4, S and 6, the remaining details of
the
system flow logically from the description provided herein, and would be clear
to one
skilled in the art. Standard 45°, 90°, doglegs and other corners
can easily be pre-
fabricated, each of these mullions being notched in the same way as the other
vertical
mullions.
[0080] An embodiment of the invention is to be marketed by Sota Glazing under
the
Hybrid-Wall~ name.
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CA 02510989 2005-06-28
METHOD OF INSTALLATION
[0081 ] The installation of the system of the invention is done in a way that
is very
similar to curtain wall systems. Firstly, the rigid panels are pre-assembled
per step
110 of Figure 10. Typically, the rigid panels 40 of the invention are shipped
with the
anchors 74, 76 already slipped into the vertical mullions per step 112, and
are held
there using tape or a temporary fastener, such as a sheet metal screw. This
temporary
fastener can be placed in a location that will not be visible once the
installation is
complete.
[0082] Per step 114, the rigid panels 40 are then hung from a little hoist
from an upper
floor, and are moved into position, adjacent to a rigid panel which has
already been
installed, and approximately three or four inches about its final installed
position.
Each rigid panel is interlocked with the adj acent rigid panel, the two halves
of the
vertical split mullion being snapped together.
[0083] The rigid panel 40 is adjusted and fastened per step 116 by lowering it
down
until it engages with the horizontal air seal gasket 66. Once that is done,
the anchors
74, 76 are simply pushed from the vertical mullions until they are flush with
the
surfaces of the concrete floor slabs 16, 16', the rigid panel 40 is plumbed,
and the
anchors 74, 76 are fastened to the slabs 16, 16'.
[0084] Then, using self tapping screws or similar fasteners, the screws are
fastened
through the vertical mullions and the sleeves at the bottom, to create a dead
load
connection.
[0085] The interior extruded aluminum closure trim 80, horizontal snap-on trim
cover
82 and any other finishing can now be installed on the interior. Finally, the
system
can then be fire-safed as required, and the installation is complete.
ADVANTAGES
[0086] The system of the invention provides a blend of conventional curtain
wall and
window wall systems. A curtain wall system is considered a high cost but best
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CA 02510989 2005-06-28
performing fenestration building envelope, cladding system for high rise
buildings.
The window wall system is considered a lower cost and lower performing
building
envelope cladding system. The primary advantage of the system of the invention
is to
combine the superior performance and design flexibility of a conventional
curtain wall
system with the economical advantage of a conventional window wall system.
[0087] The main market for the system of the invention is residential
condominium
projects where developers have bought building envelope systems based purely
on
price. New energy codes and higher performance requirements due to taller
structures
have pushed conventional window wall systems to their performance limits. The
system of the invention is capable of meeting all higher performance and
aesthetic
requirements at a minimal price increase to present window wall costs.
[0088] As noted in the Background of the Invention, window wall systems often
have
a "prison look". The rigid panels of the window walls are installed between
the slabs,
so there are necessarily numerous horizontal bars. Because window wall systems
are
designed with smaller and weaker structural mullions, designers are forced to
use
more of them, resulting in more vertical lines. Currently, vertical mullions
in window
wall systems are spaced on the order of between three- and four- foot centers,
while
the invention typically uses four- to five-foot centers. Thus, the systems of
the
invention opens up more vision area and results in less metal lines. The
invention can
use fewer vertical mullions because it is actually more economical with the
design of
the invention to do so. Fewer vertical mullions makes for fewer anchors to
install,
and faster and less-expensive installation.
[0089] Also as noted above, window wall systems have a single seal from the
outside,
like a fish tank, meaning if the exterior field breaks down, water will run
into the
building. With the system of the invention there is a dual line of defense,
because it is
a curtain wall system. There is an exterior line of defense via the continuous
vision
glass/spandrel glass cladding, and a secondary air seal line in the centre of
the system.
So, if the exterior breaks down, the secondary line will take over and defend
the
infiltration. The window wall does not have that; it is a single line of
defense system.
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CA 02510989 2005-06-28
[0090] ADDITIONAL OPTIONS AND ALTERNATIVES
[0091 ] The present invention has been described with regard to several
embodiments.
However, it will be apparent to persons skilled in the art that a number of
variations
and modifications can be made without departing from the scope of the
invention as
defined in the claims.
[0092] All of the finished surfaces are flexible in respect of how they are
finished.
The exterior glass, for example, are usually determined by cost and the
architectural
design and may be any colour, tinted or coloured, opaque, laminated glass,
double-
laminated, blast-proof, or bomb-proof, etc.
[0093] The exterior of the wall can also be finished with large or small caps,
sunshades, etc. Most of these finishes are architectural and have nothing to
do with
the system of the invention per se.
[0094] Basically everything is part of the unitized module except the anchors
themselves, the insulation and fireproofing and whatever trim pieces might be
required.
[0095] CONCLUSIONS
[0096] There are no special requirements to implement the system of the
invention.
Most existing curtain wall systems could be modified in the manner of the
invention
to gain the same advantages. It is straightforward to modify most existing
curtain wall
systems to exploit the inventions advantages of lower price, ease of
installing
firesafing between floors, and improvements to sound attenuation between
floors.
[0097] While the invention has been described in connection with a specific
embodiment thereof and in a specific use, various modifications thereof will
occur to
those skilled in the art without departing from the spirit and scope of the
invention as
set forth in the appended claims.
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